TWI743353B - Workpiece processing method - Google Patents

Abstract

[Problem] The present invention provides a workpiece processing method capable of dividing a workpiece having resin layers on both sides of a transparent substrate into wafers in a simple method. [Solution] A method for processing a plate-shaped workpiece, the workpiece has a transparent substrate, a first resin layer laminated on the front surface of the substrate, and a second resin layer laminated on the back surface of the substrate, and the first resin layer interacts with each other A plurality of staggered predetermined dividing lines are divided into a plurality of regions. The workpiece processing method is characterized in that it includes: an adhesive step of attaching an expandable adhesive tape to the second resin layer of the workpiece; a holding step, by the adhesive Adhesive tape holds the workpiece with the chuck table of the laser processing device; the resin layer removal step is to irradiate the workpiece with a laser beam with a wavelength that is absorptive for the first resin layer and is transparent for the transparent substrate, The first resin layer is removed by ablation along the planned dividing line; the modified layer forming step, after the resin layer removal step is implemented, the mine is removed through the area on the front side of the first resin layer that has been removed. The beam is irradiated on the workpiece, and a modified layer with a refractive index or mechanical strength different from the surroundings is formed along the predetermined dividing line inside the transparent substrate; and a dividing step, after performing the modified layer forming step, expand the The adhesive tape is adhered, and the transparent substrate and the second resin layer on the back side are broken along the planned division line using the modified layer as a breaking point to divide the workpiece into wafers.

Description

Workpiece processing method

The present invention relates to a workpiece processing method for processing plate-shaped workpieces such as interposer substrates.

In order to assemble semiconductor chips or various electronic parts to the motherboard, because the electrode pitch of the semiconductor circuit is very small, since it is impossible to directly assemble the semiconductor chip to the motherboard, in order to expand the pitch between the electrodes and ensure the conduction with the motherboard pad The intermediate layer used is conventional.

The interposer is manufactured by dividing the interposer substrate with the redistribution layer on the front and back sides of the substrate into chips along the planned dividing line (for example, see Japanese Patent Application Laid-Open No. 2001-196743).

The interposer substrate is made of glass epoxy substrate, glass substrate, ceramic substrate, etc., on both the front and back of these substrates, a resin layer with a conductive pattern (pattern) composed of copper is laminated to form a heavy Cloth layer.

Traditionally, in order to divide the interposer substrate into individual interposer wafers, different processing is performed on the front side, substrate, and back side of the interposer substrate to separate the interposer substrate into individual interposer wafers. .

For example, the redistribution layer on the front side is removed by ablation by the irradiation of a laser beam, and then the inside of the substrate is irradiated with a laser beam of a wavelength that is penetrating to the substrate to form a modified layer, and then the substrate is reversed up and down. , The redistribution layer on the back surface is irradiated with the laser beam and removed by ablation, so as to divide the entire interposer substrate into individual interposer wafers. [Literature Technical Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2001-196743

[Problem to be Solved by the Invention] However, in the conventional laser processing method, there are two types of laser oscillators, namely, the laser oscillator used to remove the redistribution layer by ablation and the laser oscillator used in the substrate The laser oscillator to form the modified layer is necessary, and after the modified layer is formed in the substrate, it is necessary to invert the substrate up and down to perform ablation to remove the heavy layer on the back side. It is manufactured due to the complexity of the process. Costly problem.

In view of this, the present invention aims to provide a workpiece processing method capable of dividing a workpiece with resin layers on both sides of a transparent substrate into wafers in a simple manner.

[Technical Means for Solving the Problem] According to the present invention, there is provided a method for processing a plate-shaped workpiece having a transparent substrate, a first resin layer laminated on the front surface of the substrate, and a second resin layer laminated on the back surface of the substrate, and The first resin layer is divided into a plurality of regions by a plurality of intersecting predetermined dividing lines, and the workpiece processing method is characterized by including: an adhesive step of attaching an expandable adhesive tape to the second resin layer of the workpiece ; Holding step, the workpiece is held by the chuck table of the laser processing device by the adhesive tape; the resin layer removal step, the first resin layer is absorbing and transparent to the transparent substrate with a wavelength The laser beam is irradiated on the workpiece, and the first resin layer is removed by ablation along the predetermined dividing line; the modified layer forming step, after the resin layer removal step is implemented, the first resin layer is removed through The area on the front side irradiates the aforementioned laser beam on the workpiece, and forms a modified layer with a refractive index or mechanical strength different from the surroundings along the predetermined dividing line inside the transparent substrate; and the dividing step is performed after the modification After the quality layer formation step, the adhesive tape is expanded, and the transparent substrate and the second resin layer on the back side are broken along the planned division line using the modified layer as a breaking point to divide the workpiece into wafers.

Preferably, the first and second resin layers are redistribution layers, and the workpiece is an interposer substrate. Preferably, the modified layer is composed of a shield channel, and the shield channel is composed of pores and a metamorphic area of a transparent substrate that shields the pores. Preferably, the shield channel formed inside the transparent substrate is formed to expose the front or back of the substrate.

[Effects of the invention] According to the processing method of the present invention, when the transparent substrate is broken along the planned dividing line by the expansion of the adhesive tape, the second resin layer on the back side will be broken together with the substrate, and there is no opposition to the second resin layer on the back side. It is necessary for the resin layer to perform ablation processing, and the workpiece can be divided into wafers with a laser beam irradiating only the workpiece from the front side.

In addition, taking advantage of the difference between the transparent substrate and the resin, because the laser beam of a single wavelength that is absorbing to the resin layer and transparent to the transparent substrate can be used to achieve ablation processing to remove the resin layer and in the transparent substrate The internal processing that forms the starting point of the fracture can achieve the effect of not having to prepare two different wavelength oscillators.

Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1(A), the plate-shaped workpiece 11 is composed of an interposer substrate in this embodiment, and the interposer substrate 11 is formed by laminating a first resin layer 15 on the front surface of a transparent substrate 13 and a back layer The second resin layer 17 is accumulated.

In this embodiment, both the first resin layer 15 and the second resin layer 17 are re-layed layers, which are formed by embedding conductive patterns in resin. In addition, the transparent substrate 13 is composed of a glass substrate in this embodiment, and a plurality of through holes connecting the conductor pattern of the first resin layer 15 and the conductor pattern of the second resin layer 17 are formed in the glass substrate 13.

In the processing method of this embodiment, first, a tape sticking step of sticking the second resin layer 17 side of the interposer substrate 11 to the expandable adhesive tape T is carried out. The outer periphery of the adhesive tape T is mounted on the ring frame F on. When the tape sticking step is performed, as shown in FIG. 1(B), the interposer substrate 11 will be in a state of being supported by the ring frame F by the sticking tape T.

In addition, in this specification, although the interposer substrate 11 is used as the work to be described, the plate-shaped work is not limited to the interposer substrate. The processing method of the present invention can be applied to the general case where the transparent substrate has resin layers on both sides. Artifact.

After the tape sticking step is performed, when the first resin layer 15 laminated on the front surface of the transparent substrate 13 is removed along the planned dividing line 19, the interposer substrate 11 is placed on the chuck table of the laser processing device by the adhesive tape T 10 is sucked and held, and the ring frame F is clamped and fixed with a jig 12 (holding step).

After the holding step is performed, as shown in FIG. 2(A), the laser beam LB (whose wavelength is absorptive to the first resin layer 15 and transparent to the transparent substrate 13) is condensed by the condensing lens 16 The device 14 condenses and irradiates the first resin layer 15, and by processing and feeding the chuck table 10 in the arrow X1 direction, the first resin layer 15 is removed along the planned dividing line 19, and the implementation is shown in FIG. 2(B) The resin layer removal step of forming the processing groove 21 is shown.

The indexing feed is performed at the pitch of the planned dividing line 19 in a direction orthogonal to the X1 direction of the processing feed direction, and this resin layer removal step is sequentially performed along the planned dividing line 19 extending in the first direction. Next, after rotating the chuck table 10 by 90 degrees, the same resin layer removal step is performed along all the planned dividing lines 19 extending in the second direction orthogonal to the first direction.

The laser processing conditions of the resin layer removal step are set as follows, for example.

Light source: Laser diode (LD) excited Q switch Nd: YAG pulse laser Wavelength: 355nm (the third harmonic of YAG laser) Repetition frequency: 200kHz Average output: 15W Processing feed rate: 500mm/s

After the resin layer removal step is performed, the modified layer formation step is performed: through the area on the front side of the first resin layer 15 that has been removed along the planned dividing line 19, the laser beam LB used in the resin layer removal step The laser beam LB of the same wavelength is irradiated to the glass substrate 13, and a modified layer is formed along the planned dividing line 19 inside the transparent glass substrate 13.

The modified layer includes a region in which the refractive index, mechanical strength, or other physical properties are different from the surroundings. As the modified layer forming step, a shield tunnel forming step is implemented, which forms a modified layered shield channel suitable as the starting point of fracture.

In the laser processing method of this embodiment, since the ablation processing of the first resin layer 15 and the laser processing of the glass substrate 13 are performed with a laser beam of the same wavelength, a lens with a numerical aperture (NA) not too large is used as a condenser. For the condenser lens 16 of the optical device 14, for example, a condenser lens 16 having a numerical aperture of approximately 0.1 to 0.3 is preferably used. Furthermore, it is preferable that the condenser lens 16 has a certain degree of spherical aberration.

In the step of forming the shield channel, as shown in FIG. 3(A), the laser beam LB from the condenser 14 is removed by positioning the condensing point P1 under the second resin layer 17 close to the glass substrate 13 The processing groove 21 of the first resin layer 15 is irradiated, and by processing and feeding the chuck table 10 in the direction of arrow X1, as shown in FIG. The shield channel 23 is formed by the pore 25 and the deteriorated area 27 of the glass shielding the pore 25.

The pores 25 of the shield channel 23 preferably expose the front and back surfaces of the glass substrate 13. The strength of this shield channel 23 is lower than that of its surroundings, and it becomes the starting point of fracture for the subsequent segmentation step.

While indexing and feeding the chuck table 10 at the pitch of the planned dividing line 19 in the direction orthogonal to the machining feed direction X1, it is implemented along all the planned dividing lines 19 extending in the first direction.

Next, after rotating the chuck table 10 by 90 degrees, the same shield passage forming step is also performed along all the planned dividing lines 19 extending in the second direction orthogonal to the first direction.

The laser processing conditions of the shield channel forming step are set as follows, for example.

Light source: Laser diode (LD) excited Q switch Nd: YAG pulse laser Wavelength: 355nm (the third harmonic of YAG laser) Repetition frequency: 200kHz Average output: 15W Processing feed rate: 500mm/s

Next, referring to FIG. 4, the steps of forming a shield passage in the second embodiment of the present invention will be described. In the shield channel forming step of the second embodiment, the laser beam irradiation system is divided into two times.

First, as shown in FIG. 4(A), the focal point P1 of the laser beam LB is positioned near the second resin layer 17 in the glass substrate 13 and irradiated across the processing groove 21 formed on the first resin layer 15 The laser beam LB is formed inside the glass substrate 13, and a shield channel 23 a composed of a pore 25 extending from the back of the glass substrate 13 to a half and a deterioration area 27 of the glass shielding the pore 25 is formed in the interior of the glass substrate 13.

In the first step of the step of forming the shield channel, the shield channel 23a extends halfway to the front of the glass substrate 13 due to the suppression of the power of the laser beam LB.

Next, perform the second step of the shield channel forming step shown in FIG. 4(B). In the second step, the condensing point P2 of the laser beam LB is positioned approximately in the middle of the thickness direction of the glass substrate 13, and the laser beam LB is irradiated across the processing groove 21 formed on the first resin layer 15 and divided along the split The predetermined line 19 forms a shield channel 23 composed of a pore 25 extending to the front surface of the glass substrate 13 and a deteriorated area 27 of the glass shielding the pore 25. When this second step is implemented, the pores 25 of the shield channel 23 will expose the front and back sides of the glass substrate 13.

As in the second embodiment, if the shield channel forming step is divided into the first step and the second step and implemented twice, the power of the laser beam LB can be suppressed, and the shield channel 23 with better quality can be formed.

The laser processing conditions in the shield tunnel formation step of the second embodiment are set as follows, for example.

Light source: laser diode (LD) excitation Q switch Nd: YAG pulse laser wavelength: 355nm (the third harmonic of YAG laser) Repetition frequency: 200kHz Average output: 10W in the first step, 7W in the second step Feeding speed: 500mm/s

After the shield channel forming step is performed, the adhesive tape T to which the interposer substrate 11 is pasted is expanded, and the shield channel 23 formed inside the glass substrate 13 is used as the starting point of fracture along the planned dividing line 19 to separate the glass substrate 13 and the second The resin layer 17 is broken to implement the dividing step of dividing the interposer substrate 11 into individual interposer wafers.

This segmentation step, for example, as shown in FIG. 5, is implemented using an expansion device 20. The expansion device 20 is composed of an outer tube 22 and a cylindrical pressing member 26 housed in the outer tube 22 and having a diameter smaller than the diameter of the ring frame F and larger than the diameter of the interposer substrate 11.

Above the outer cylinder 22, a plurality of (for example, four) clamps 24 are arranged at equal intervals. The cylindrical pressing member 26 is moved in the vertical direction between the reference position shown in FIG. 5(A) and the push-up position shown in FIG. 5(B) by a driving means not shown.

In the dividing step, first, as shown in FIG. 5(A), with the cylindrical pusher member 26 positioned at the reference position, the interposer substrate 11 is placed on the cylindrical pusher by the adhesive tape T On the member 26, the clamp 24 of the outer tube 22 clamps and fixes the ring frame F.

Next, as shown in FIG. 5(B), the cylindrical pressing member 26 is pushed in the arrow A direction. By pushing up the cylindrical pressing member 26, the expansible adhesive tape T is expanded mainly in the radial direction, and the glass substrate 13 adhered to the interposer substrate 11 of the adhesive tape T is broken with the shield channel 23 as the starting point of fracture. The second resin layer 17 laminated on the glass substrate 13 is also broken at the same time, and the interposer substrate 11 is divided into individual interposer wafers 31.

In the above-mentioned embodiment, the first resin layer 15 on the front side of the glass substrate 13 is removed by ablation of the laser beam along the planned dividing line 19, and has the same wavelength as the ablation process in the glass substrate 13 After the laser beam forms the shield channel 23 as the starting point of division, the adhesive tape T is expanded by the expansion device 20 to apply external force to the interposer substrate 11, because the second resin layer 17 on the back side and the glass substrate 13 is divided into individual interposer wafers 31, so there is no need to ablate the second resin layer 17 on the back side, and the interposer substrate 11 can be divided into individual wafers 31 by irradiating the laser beam LB from the front side only. .

By using the properties of absorption of the first resin layer 15 with respect to the wavelength of the laser beam and penetration of the glass substrate 13, the ablation process for removing the first resin layer 15 can be achieved with a single wavelength laser beam such as 355nm , And the internal processing to form the fracture origin in the transparent substrate 13, so there is no need to prepare two laser oscillators that oscillate lasers of different wavelengths.

In addition, in the above-mentioned embodiment, a laser beam with a wavelength of 355nm is used for a laser beam with a transparent substrate having a penetrating wavelength, but the second harmonic of a YAG pulse laser as a laser beam may also be used That is, a pulsed laser beam with a wavelength of 532nm.

10‧‧‧Chuck table 11‧‧‧Interposer substrate 13‧‧‧Glass substrate (transparent substrate) 14‧‧‧Concentrator 15‧‧‧The first resin layer (relay layer) Lens 17‧‧‧Second resin layer (heavy cloth layer) 19‧‧‧Preparation line 20‧‧‧Expansion device 21‧‧‧Processing groove 22‧‧‧Outer cylinder 23‧‧‧Shield channel 25‧‧‧ Pore 26‧‧‧Cylindrical pressing member 27‧‧‧Deteriorated area 31‧‧‧Interposer chip

Fig. 1(A) is a perspective view showing a tape sticking step, and Fig. 1(B) is a perspective view showing a state where the tape sticking step is performed and the interposer substrate is supported by a ring frame by the adhesive tape. 2(A) is a partial cross-sectional side view showing the resin layer removal step, and FIG. 2(B) is an enlarged cross-sectional view of the interposer substrate shown in FIG. 1. FIG. 3(A) is a partial cross-sectional side view showing the steps of forming a shield channel, and FIG. 3(B) is an enlarged cross-sectional view of the interposer substrate shown in FIG. 1. Fig. 4(A) is a cross-sectional view illustrating the state where the condensing point of the laser beam is positioned close to the second resin layer, and Fig. 4(B) is a schematic diagram illustrating the position of the condensing point of the laser beam in the thickness direction of the substrate A cross-sectional view of the state of the central part. Fig. 5 is a cross-sectional view showing the dividing step.

10‧‧‧Chuck table

11‧‧‧Interposer substrate

12‧‧‧Fixture

13‧‧‧Glass substrate (transparent substrate)

14‧‧‧Concentrator

15‧‧‧The first resin layer (heavy cloth layer)

16‧‧‧Condenser lens

17‧‧‧The second resin layer (heavy cloth layer)

21‧‧‧Processing groove

23‧‧‧Shield Passage

25‧‧‧Fine holes

27‧‧‧Deteriorated area

F‧‧‧Ring frame

LB‧‧‧Laser beam

P1‧‧‧Spotlight

T‧‧‧Tape

X1‧‧‧Arrow

Claims (4)

A workpiece processing method for dividing a plate-shaped workpiece. The workpiece has a transparent substrate, a first resin layer laminated on the front of the substrate, and a second resin layer laminated on the back of the substrate, and the first resin layer is borrowed The workpiece processing method is divided into a plurality of regions by a plurality of intersecting predetermined dividing lines. The workpiece processing method is characterized by including: an adhesive step of sticking an expandable adhesive tape to the second resin layer of the workpiece; a holding step, by The adhesive tape holds the workpiece with the chuck table of the laser processing device; the resin layer removal step is to irradiate the laser beam with a wavelength that is absorptive to the first resin layer and transparent to the transparent substrate. Work piece, and remove the first resin layer by ablation along the planned dividing line; the modified layer forming step, after the resin layer removal step is performed, pass through the area on the front side where the first resin layer has been removed The aforementioned laser beam is irradiated on the workpiece, and a modified layer having a refractive index or mechanical strength different from the surroundings is formed along the predetermined dividing line inside the transparent substrate; and the dividing step, after the modified layer forming step is implemented, The adhesive tape is expanded, and the transparent substrate and the second resin layer on the back side are broken along the planned division line using the modified layer as a breaking point to divide the workpiece into wafers. According to the workpiece processing method described in the first item of the scope of patent application, the modified layer is composed of a shield channel, and the shield channel is composed of pores and a modified region of the transparent substrate that shields the pores. The workpiece processing method as described in the first item of the scope of patent application, wherein the aforementioned first and second resin layers are redistributed layers, and the workpiece is an interposer substrate. According to the method for processing the workpiece described in item 2 of the scope of patent application, the shield channel exposes the front or back of the transparent substrate.

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